Basin seeder



Sept. 28, 1954 F. ROMAIN 2,690,145

BASIN SEEDER Filed Jan. 19, 1950 5 Sheets-Sheet l Sept. 28, 1954 F, MN 2,690,145

BASIN SEEDER Filed Jan. 19, 1950 5 Sheets-Sheet 2 kit-W051.

F. ROMAIN BASIN SEEDER Sept. 28, 1954 5 Sheets-Sheet 3 Filed Jan. 19, 1950 Sept. 28, 1954 F. ROMAIN 2,690,145

BASIN SEEDER Filed Jan. 19. 1950 5 Sheets-Sheet 4 Sept. 28, 1954 F. ROMAIN 2,690,145

BASIN SEEDER Filed Jan. 19, 1950 5 Sheets-Sheet 5 Patented Sept. 28, 1954 UNITED STATES TENT OFFICE BASIN SEEDER Fred Romain, Chester, Mont.

Application January 19, 1950, Serial No. 139,490

3 Claims.

This invention pertains to improvements in grain drills and more particularly to a basin seeder adapted to sow seed in depressed cavities or pockets below the normal surface of the ground.

One of the objects of this invention is to provide a grain drill or basin seeder which is adapted to sow seed and prepare the soil surface in such a way as to minimize wind erosion and reduce water run-off and at the same time effect a greater retention of rainfall and drifting snow in the soil.

Another object of this invention is to construct a basin seeder or drill which first digs a series of depressed basin shaped cavities, pockets or holes in the soil surface, next deposits desired quantities of seed in each pocket, then deposits a suitable light covering of soil on the seeds, and finally, firmly packs the covered seed in the bottom of the pockets, the whole operation being carried out in an automatic and continuous manner.

Still another object of this invention is to provide a basin seeder which may be passed over the surface of a field so as to plant the seed in a series of closely spaced depressed basins or pockets, which pockets remain intact during the growing period of the grain so as to entrapdrifting snow and soil and retain a maximum of rainfall, increase the retained moisture in the soil, and bring about a greater yield per acre than with former methods of planting.

Still another object of this invention is to have a grain drill arranged to sow seed in a series of depressed pockets in the field surface to control erosion and increase retention of moisture, which grain drill may be operated over the land surface independent of considerations of topography and land contour, while at the same time giving effective control of the soil surface for any degree of steepness of slope to be seeded.

And a further object is toprovide a grain drill capable of sewing seed in soil containing a high degree of overlying straw mulch.

Further features and advantages of this invention will appear from a detailed description of the drawings in which:

Figure 1 is a plan View, partly broken away, of a grain drill incorporating the features of this invention.

Figure 2 is a right hand side elevation of the grain drill indicated by the line 2-2 in Figure 1.

Figure 3 is an enlarged fragmentary sectional view on the line 3-3 of Figure 1.

Figure 4 is a fragmentary section on the line 4-4 of Figure 3.

Figure 5 is a transverse sectional view on the line 55 of Figure 1.

Figure 6 is an enlarged fragmentary section on the line B$ of Figure 1.

Figure 7 is a fragmentary sectional view on the line 1-1 of Figure 6.

Figure 8 is a section on the line 8-8 of Figure 7.

Figure 9 is a fragmentary section on the line 98 of Figure 8.

Figure 10 is a perspective view of the seed brush shown in Figure 8.

Figure 11 is a sectional view on the line lI-l l of Figure 1.

Figure 12 is a sectional view on the line 12-42 of Figure 1.

Figure 13 is an enlarged sectional view on the line I 3-13 of Figure 2.

Figure 14 is a sectional view on'the line 14-14 of Figure 13.

Figure 15 is a sectional view on the line l5l5 of Figure 13.

Figure 16 is a sectional view on the line l6-l 6 of Figure 13.

Figure 1'7 is a sectional view on the line "-1 "i of Figure 14.

Figure 18 is a sectional view on the line iii-48 of Figure 14.

Figure 19 is a sectional view on the line l9l 9 of Figure 13.

Figure 20 is a sectional view on the line 2ll20 of Figure 13.

Figure 21 is a diagram showing the arrangement of the depressed cavities formed in the soil surface by the grain drill.

As illustrative of one embodiment of a grain drill incorporating the features of this invention, there is shown a drill having a main frame 25, Figure 1, consisting of the front member 26, the rear member 21, and the side members 28 and together with the members 3d, 3!, 32, 33 and 34 located parallel to the side members, the members 35 and 36 located parallel to the front and rear members, and the angular braces 31 and 313, all rigidly secured together. The front portion of the main frame is supported on steerable Wheels 39 and it which are carried on suitable steering knuckles 4! and 42 arranged to swing about vertical axes d3 in the bearings 44 and 45 fixed at their upper ends to the front member 26 and connected at their lower ends through the tie rods 46 and ii to the member 36 of the frame, Figures 2 and 5. The steering knuckles 4i and 42 are connected through drag links 48 and 69, to the pivot pin 5%, fixed on the towing arm or tongue 51 which in turn is pivotally mounted for swinging about a vertical axis 52 in a bearing 53 secured to the front member 26 of the frame. The tongue i is hitched. to a suitable tractor which may readily tow the drill in any desired direction by this steering arrangement.

The rear portion of the main frame 25 is supported on. a seriesof packer wheels Pi and P2, Figure 1, carried on the respective packer shafts 54 and 55. The detailed construction of the packer shaft arrangement is best shown in Figure 13. The shaft 55-} is preferably of square cross section and carries a series of spacing members, 56 through 82 inclusive, each of which has square bores nicely fitting over the shaft Similarly, there are provided spacing members, through I0, inclusive, Figure 1, on the shaft Support-- ing bearing surfaces I! and if formed on the respective members 55 and ti, and Si and 82, are journaled in suitable bearings I3 and Ed on the downwardly extending angular brackets and it while the shaft 5d is'sirnilarly supported on bearings TI and 18 on the brackets 19 and 83.

Each of the packer wheels Pi and P2'comprises a series of radially projecting arms 3!, six in number in this particular embodiment, which terminate in spherical end portions 52 which roll in meshing relationship with preformed basins in the soil surface. These wheels may be preferably constructed of two half pieces formed as steel stampings as best shown in Figures l3, 14, 17, and 18. The two half pieces of Figures 17 and 18 are placed together and welded along the line 83 to form the complete packer wheel unit. The wheel is constructed with a round bore 8A which nicely fits over the edges of the square shafts 54 and 55 to properly center the packer wheels on these shafts. One of the side faces of the hub of the packer wheels is formed with serrations or teeth t5 meshed with mating teeth or serrations 86 on the spacing members 5t, 53, and 5d, and slip clutch member welded to the shaft 55, and 65, 66, 68, and 'm for the shaft 54. The purpose of this arrangement is to make it possible to position and lock each of the packer wheels relative to each other so that the spherical end portions 82 can be arranged in a helically disposed manner as best seen in Figures 1 and 2, and may be positively held in this position under all operating conditions. In order to look all of the packer wheels PI together as described, the shaft 5 3 is securely welded at at to the cup member 88, Figure 13, and has a clamping washer BS and binding nut 98 at its other end, Figure l, which may be tightened down to thus look all of the packer wheels securely to the shaft 5 3. The shaft 55 has fixed on it a nut EH which confines a compression spring 92, Figure 13, up against the face 93 of the slip clutch member 9 5 and on its other end is a clamping nut 935 bearing against a clamping washer $6 for holding the packer wheels P2 together while at the same time allowing a limited axial shifting of the member 94- relative to the shaft 55.

Both of the shafts 5d and 55 are normally retained in a predetermined indexed position relative to one another so as to maintain the afora mentioned helical arrangement of the basin contacting spherical end portions c2 of the packer wheels Pi and P2. However, in instances where the grain drill is operated in short turns, it is desirable to have one or the other of the groups PI or P2 of packer wheels rotate ahead of the other. During this condition the advance of one group over'the other is effected instantaneously from one indexed position to another so as to avoid any gradual or intermediate spacing of the packer wheels and basins formed by one group relative to the other in making short turns at the end of a field. To this end there is provided a series of raised portions ill, Figure 15, on the cup member M which are arranged to engage in mating depressed detent cavities 98 formed in the member 63, Figure 16. The member 94 is free to rotate relative to the shaft 55, but normally maintains the drive through the slip clutch members 9 and 63 except when exceptionally sharp turns are made. In order to effect an instantaneous shift from one indexed position to another of the members 9T98, there is provided a torsion spring 99 having one of its ends fixed at I00 to the member 94 and having its other end fastened at Iill to the member 88 so that as the grain drill is driven around a turn, the spring 99 initially tends to prevent shifting of the members 9'I98 by providing a certain amount of yieldingly drive between shafts E i'and 55, but as the turn is continued additional torsion is built up in the spring 99 until finally the members 91 and 98 instantly shift relative to one another to a new indexed position for the shafts 5d and 55. The spacing of the members 97 and 98 is so arranged in relation to the spacing of the spherical ends 82 of the packer wheels that the two groups Pi and P2 are always kept in proper indexed relationship to maintain the desired helical arrangement of the ends 83. Preferably the end portions 82 may be covered with rubber or the like material 82 a, as such materials have less tendency for the soil to adhere to these portions and it also provides a more satisfactory condition when transporting the grain drill over hard surfaced roads.

Movably mounted on the main frame 25 for vertical adjustment relative to the soil surface S are the two groups of digger wheels DI and D2. Each of the digger wheels, Figure 11, comprises a series of radially disposed curved basin digging blades I62 equal in number and spacing to the arms 8'! of the packer wheels. Each ofthe blades W2 is rigidly fixed by a suitable bracket N13 to the periphery of a hollow drum shaped hub member Hi l which has an opening I65 on one side and a serrated portion Hi6, similar to the portions of the packer wheels, on the hub portion IN. A round bore Hi1, Figure 11, serves to nicely center the digger wheels DI and D2 on the respective digger shafts I08 and H35. Spacing spools H0, Figures 1 and 7, having mating serrated portions I l I engaging the serrated portions We of the digger wheels, serve to properly position and hold the digger wheels with the ends H2 of the blades I02 in the same desired helically disposed position as that of the packer wheel ends '82. The digger Wheel shafts I08 and I09 are respectively journaled in suitable bearings H3 and H4, Figure 1, carried on the respective bails H5 and lit. The bail H5 is universally mounted'at I H for articulated movement on the front portion of the main frame 25 while the bail I It is similarly mounted at I I8. Each of the bails H5 and H6 is thus free to swing the shafts I63 and W9 up and down in a vertical direction and to allow either end of the bail to move up and down independently relative to the ground surface S as indicated by the line H9 in Figure 5. Stabilizer links I20 and IZI are connected at I22 and I23 to the balls H5 and M5, the links being connected at 124% and I25 to the main frame in order to key the diggers DI and D2 in alignment with the ends 82 of the packer wheels.

The rear ends of the bails H5 and I I6 have lugs I26 through which pass the eye bolts I21. A suitable adjusting nut and washer I 2611 are provided on the eye bolts below the lugs I26. The eye bolt I21 are pivotally connected at I28 to a series of lever arms I29 secured to the rock shaft I30 journaled on suitable bearings I3I carried on the main frame 25. Compression springs I32 are confined between the upper side of the lugs I26 of bails H5 and H6 and abutment washers I33 adjacent to the pivot pins I28 so as to normally hold lugs I26 of the bails down against the nut and washer I261) while at the same time providing resilient yielding means to allow the bails to be moved forcibly upwardly compressing the springs I32 in the event a rigid obstruction, such as a rock or a root, should be encountered by the diggers and thereby avoid damage to the apparatus. By adjusting the nut and washer I262), the effective force of the springs I32 may be regulated in accordance with the character of the soil being worked, so that the digger wheels remain at'full depth as set by lever I34 except when an obstruction is encountered.

The depth of digging is regulated by the position of the control lever I34 pivotally mounted at I35 on the main frame 25 and havin a pivotal connection I36 connected to a link I61 which in turn is comiected at I38 to the lever arm I39 fixed to the rock shaft I 30 so that swinging of the lever I34 effects raising and lowerin of the bails H5 and I I6. A suitable latch I46 engaging in the notches IM or the latch segment I42 fixed to the main frame 25 is controlled by the release lever I43 in a suitable manner so that the lever I34 and the depth of the digger of the blades I02 may be set to any desired position.

The packer wheels PI and digger wheels DI are rotated in synchronism to keep the ends II2 of the digger blades in proper timed relationship with the ends 82 of the packer wheels by means of the driving chain I44, Figures 1 and 5, which operates over a sprocket I45 fixed to the packer shaft 54 and over a sprocket I46 fixed to the digger shaft I08. The chain also passes over a sprocket I41 fixed to the shaft I48 journaled on suitable bearings I49 and I50 fixed to the members 30 and 3I on the main frame 25. Similarly,

the packer shaft is provided with a sprocket I5I, Figures 1 and 3, over which operates the chain I52 which chain in turn operates over a sprocket I53 fixed to the digger shaft I09 and also over the sprocket I54 fixed on the shaft I55 which is journaled in suitable bearings I 55, I51, and I58 on the members 33, 34, and 29 respectively of the main frame 25. Referring particularly to Figures 3 and 4, both of the chains I44 and I52 are kept in proper tension at all times for any adjusted position of the cradles H5 and III; by means of the tension rollers I59 journaled at I60 on the outer ends of the links I6I pivotally supported at I62 on the brackets I63 fixed to the members 30 and 34 of the main frame 25. The links I'6I are normally pulled upwardly by the tension springs I64 to force the rollers I59 yieldingly into engagement with the chains I44 and I52.

Seed is provided for the drill by means of a conventional hopper mechanism I65, shown broken away in Figure l to better illustrate the machine, which is mounted on suitable supports I66 on the main frame 25. The hopper mechanism I is driven by the rotation of the packer wheels as the grain drill is pulled over the field. This mechanism comprises a sprocket I61 fixed to the shaft I55, Figures 1 and 2, over which operates the driving chain I50 which in turn operates over the sprocket I69 of a suitable clutch I10 journaled on the shaft I II journaled on suitable bearings I12 and I19 carried on the members 34 and 29 of the main frame 25. A suitable clutch operating member I14 is connected through a lever arm I15 and the link I16 to a lever arm I11 fixed to the rock shaft I30 so that when the lever IE4 is moved to fully retracted position of lifting of the digger wheels from the soil surface S, the. clutch I10 disconnects drive from the chain I68 to the shaft I1I. When the lever I34 is moved to lower the digger wheels to effect a digging operation, the clutch member I10 then connects the power drive from chain I68 to the shaft I1I. On the outer end of the shaft IN is a sprocket I16 over which operates a chain I19 connected to the sprocket I00 fixed on the operating shaft ISI of the seed hopper mechanism I 65.

Since the feed hopper I65 is of conventional construction, the details of its construction and operation upon rotation of the shaft I6I need not be described in detail, it being sufiicient to state that a series of flexible seed conductor pipes I82, one for each of the digger wheels DI and D2, convey desired amounts of seed to be planted as the grain drill is moved over the field. A member I83, Figures 6 and 8, having a slot Iilta is provided to close the opened end I 05 of the hub portion I04 of each dig er wheel and is supported by suitable bolts I84 to appropriate bracket arms I 85 fixed to the cross rails I85 attached to the bails I I5 and H6. To the lower portion of the member IE8 is attached the segmental plate I81 by means of the bolts I88 and. the lap joint I89 as best seen in Figure 9. The seed feeding pipes I 82 are connected to the angularly downwardly positioned nozzles I00 opening at IQI, Figure 8, into the seed chamber I92 of the digger wheels DI and D2. A series of seed openings I 63 open radially outwardly from the chamber I92 through the periphery I64 of the hub portion I I14 of the digger wheels.

Pivotally mounted on a pivot screw I65 on the inner face I95 of the member I81 is the brush holder angle plate I91, shown best in Figures 8 and 10, which has a second mounting bolt I90 adjustable in an arcuate slot I99 formed in the member I81, so that the member I91 may be clamped to various adjusted positions about the pivot I 95 to vary the relative position of the seed brush 250:, fixed by suitable rivets 2III to the member I91, in regard to the inner surface 202 of the chamber I 92.

The operation of the grain drill is as follows: When the grain drill is to be transported to the location where the seeding is to be done, the control lever I34 is moved to a position I34a to fully retract the digger wheels to upward position as shown in Figure 5. The drill may then be rolled alon freely on the wheels 39 and 40 and on the packer wheels PI and P2, the helical arrangement of packer wheels permitting a smooth rolling action for the grain drill under these conditions.

When the device is to be put into operation to seed a field, the control lever I64 is moved to a desired position, as shown in Figure 2, so as to lower the digger wheels to operating position.

0 Referring to Figure 3, it is to be noted that the diameter 2.03 of the path of rotation of the edges I I2 of the digger blades W2 is of smaller size than the diameter 20A of the path of rotation of the spherical ends 82 of the packer wheels. As the grain drill moves forward, the various digger blades I02 are projected forwardly and downwardly into the soil surface. Since the operating diameter 203 of the edges I I2 is smaller than the diameter of the packer wheels, the blades 162 will form fiat bottoms 295 in the depressed holes in the soil surface S during the time the blades are extending vertically downwardly. Steep sloping sides 20$ are formed as the blades move down into the soil and, steep sloping sides 20? as they withdraw from the depressed holes in the surface S. The widened fiat bottoms 2G5 result because the periphery of the diameter of rotation 2&3 is moving slightly more rapidly at the bottom 2'65 of the hole than the actual forward movement of the axis of rotation 208 of the digger wheels, since the larger diameter 294, which takes its drive from the soil surface S, is connected to rotate the digger wheels at the same speed as the packer wheels. Seed is applied from the nozzles it] into the chambers I92 behind the brush 2%, Figure 8, which accumulates and compacts the seed into a group 269 down against the brush 200. As the hub [il -l rotates, a seed opening I93 passes under the brush 200 and then as it comes out from under the brush, the group of compacted seeds 209 drop out and fall to the bottom 205 of a hole that has just been opened by a digging blade as best seen in Figure 3.

Immediately following the digger blade, a spherical end 82 of a packer Wheel bumps the loose dirt at the point 218 at the top rear portion of a hole that has just been dug, knocking the loose soil down into the hole over the seeds deposited at 205 in the bottom of the hole, properly covering up the seeds. Continued rolling action of the packer wheel brings the spherical end to the bottom of the hole to pack the dirt securely around the seeds, as shown at 2| I and then withdraws itself out of the hole leaving the seeds properly planted in the depressed pocket below the soil surface S. Each one of the digger wheels and packer wheels perform this operation so as to produce a pattern of planting, as shown in the diagram Figure 21, so that the entire field surface s is completed with an arrangement of depressed pockets 2 l 2 as shown.

In this way the seeds are located in the soil in such a manner as to receive a maximum of run-off from the soil surface S and at the same time retain drifting snow. It is to be further noted that the action of the digger blades I02 in moving forwardly and downwardly into the soil surface S, then dragging along the bottom of the hole due to the differential speed of movement created by the greater diameter of the packer wheels over that of the digger wheels, and the upwardly and forwardly withdrawing movement of the blades from the soil particularly adapts the apparatus to soil surfaces having a high concentration of thick and matted mulch. In this way the advantage of utilizing fields with thick straw mulch on the surface can be readily undertaken.

Having thus fully described this invention and its numerous attendant advantages, it is obvious that many changes may be made in the form, construction and arrangement of the parts without departing from the spirit or scope of the invention or sacrificing its attendant advantages,

8 the form herein described being a preferred embodiment for purposes of exemplifying this invention.

The invention is claimed as follows:

1. A basin seeding implement, comprising a frame of horizontal transverse extent, dirigible soil-contacting wheels mounted on and supporting the front of said frame, a series of soil-contacting packer wheels journaled on the rear of Said frame to rotate about a horizontal transverse axis, said packer wheels being transversely spaced along said axis and supportin the rear of said frame, each of said packer wheels including a plurality of spokes radiating from said axis and spaced therearound with a soil-packing enlargement on the outer end of each spoke, a series of digger wheels supported from said frame for rotation about a generally horizontal transverse axis in front of said packer wheels by means providing for vertical swinging and lateral tilting of the axis of said digger wheels, the number of digger wheels being identical to the number of packer wheels, said digger wheels being transversely spaced the same as said packer wheels and arranged in fore-and-aft alignment there with, each of said digger wheels having digging blades extending generally radially from the axis of the digger wheels and spaced therearound the same as the spokes of the packer wheel aligned to the rear, the radial extent of said blades being less than the radial extent of said spokes, drive means interconnecting said packer wheels and said digger wheels to cause synchronized rotation of said digger wheels with rotation of said packer wheels so that said blades form basins in the soil and the soil-packing enlargements mesh with said basins to pack the same, and seeding means for discharging seed into said basins prior to packing including a distributor mounted on each digger wheel and rotatable therewith and arranged to discharge seed behind a blade into a basin bein formed in the soil by the blade; whereby passage of said implement across a field leaves a series of seeded and packed basins in the soil to entrap drifting snow, retaining snow, water and rain for increasing moisture and reducing soil erosion.

2. A basin seeding implement comprising, a frame, dirigible soil-contacting wheels mounted on and supporting the front of said frame, a series of soil-contacting packer wheels mounted on and supporting the rear of said frame arranged for rotation about and transversely spaced on a horizontal transverse axis, a plurality of radially disposed spokes peripherally spaced around each of said packer wheels, soil-packing abutment surfaces on the outer ends of each of said spokes, a series of digger wheels carried on said frame mounted for rotation about a generally horizontal transverse axis in front of said packer Wheels, the mounting of said digger wheels including means providing for vertical swinging and lateral tilting of the axis of said digger wheels, the number of digger wheels being identical to the number of packer wheels, said digger wheels being transversely spaced the same as said packer wheels and arranged in fore-and-aft alignment therewith, radially disposed digging blade on each of said digger wheels and spaced therearound the same as the spokes of the packer wheel aligned to the rear, the radial extent of said digger blades being less than the radial extent of said spokes, drive means interconnecting said packer wheels and said digger wheels to cause synchronized rotation of said digger wheels upon rotation of said packer Wheels so that said digger blades form basins in the soil, said soil-packing abutment surfaces on said packer wheel spokes engaging in meshing relationship with said basins to pack the same, and seeding means for discharging seed into said basins prior to packing including a distributor mounted on each digger wheel and rotatable in timed relationship therewith and arranged to discharge seed behind a blade into a basin being formed in the soil by the blade.

3. A basin seeding implement including, a frame, dirigible soil-contacting wheels mounted on and supporting the front of said frame, a series of soil-contacting packer wheels located in transverse axial spaced relationship to support the rear of said frame, a plurality of radially disposed spokes on each of said wheels, soil packing abutment surfaces on the outer ends of said spokes, a series of digger wheels in front of said packer wheels located in the same transverse axial spaced relationship to and aligned with said packer wheels, means supporting said series of digger wheels on said frame for vertical swinging and lateral tilting of the axis of said digger wheels, a series of radially disposed digger blades on each of said digger wheels of the same number and, peripheral spacing as the spokes of the corresponding aligned packer wheel, the radial extent of the outer ends of said blades being less than the radial extent of said spokes, drive means interconnecting said packer wheels and said digger wheels to cause synchronized rotation of said digger wheels with rotation of said packer wheels so that said blades form basins in the soil, said soil packing abutment surfaces on said spokes meshing with said basins to pack the same, and seeding means on said frame comprising means for discharging seed into said basins prior to packing including a seed distributor mounted on each digger wheel and rotatable therewith arranged to discharge seed behind a blade into a basin being formed in the soil by the blade so that passage of said implement across a field leaves a series of seeded and packed basins in 10 the soil to entrap drifting snow and rain for increasing moisture retention and reducing soil erosion.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 53,072 Wiley Mar. 6, 1866 91,867 Reister June 29, 1869 196,954 Terry Nov. 6, 1877 242,335 Lang May 31, 1881 279,027 Shortbridge June 5, 1883 331,588 Walker et a1. Dec. 1, 1885 430,451 Walker June 17, 1890 491,887 Hoffmann Feb. 14, 1893 809,716 Miller Jan. 9, 1906 811,606 Williams Feb. 6, 1906 871,617 Oestergard Nov. 19, 1907 925,565 Curtis June 22, 1909 1,060,548 Haralson Apr. 29, 1913 1,218,919 Youngren et a1 May 13, 1917 1,226,515 Hicks May 15, 1917 1,299,064 Timmons Apr. 1, 1919 1,405,001 Reichelt Jan. 31, 1922 1,615,902 Foster Feb. 1, 1927 1,689,262 Van Dan Ende Oct. 30, 1928 1,864,122 Cole June 21, 1932 2,228,389 Garey Jan. 14, 1941 2,229,746 Krause Jan. 28, 1941 2,284,172 Silver May 26, 1942 2,314,035 Dontje Mar. 16, 1943 2,359,206 Currie Sept. 26, 1944 2,406,500 Karl Aug. 27, 1946 2,551,132 Jacobus May 1, 1951 FOREIGN PATENTS Number Country Date 6,855 Germany Aug. 20, 1879 10,525 Great Britain 1845 88,028 Sweden Dec, 1, 1936 251,388 Germany Oct. 2, 1912 281,609 Italy Jan. 17, 1931 439,559 Germany Jan. 13, 1927 698,467 France Nov. 18, 1930 

